The aim of this project is to develop and test a computer assisted patient and data management system that will allow the majority of treatment of children with cancer to be carried out according to clinical research protocols by the pediatric oncologist and the patient's primary care physician. The system will print a date oriented test and medication schedule for a full phase of therapy. It will also print date-oriented patient encounter forms for each patient encounter with the specific factors to be analyzed for that encounter and transmit appropriate treatment guidelines, audit the completed encounter form for compliance with protocol specifications, store the data collected from each encounter, and report the data in variable formats requested by local researchers and other statistical centers. The project will also test the feasibility and effectiveness of having the family involved in recording interval history. The system will reduce time and effort of data managers and center oncologists in auditing patient encounter forms, in prompting for incomplete data, and in coding and manually reproducing data from patient records for submission to statistical centers. The system will be evaluated prospectively by comparison with the present manual system with respect to completeness of data recorded, compliance with the protocol rules, time and effort required by center oncologists and data managers to collect data, accuracy and amount of data transmitted to statistical centers. The system will provide a model for more efficiencient and precise data collection and patient and data management that can be adopted by a number of other centers involved in childrens Cancer Study Group.